https://www.google.com/transparencyreport/safebrowsing/diagn...
That would make you one of the 600 million people using that service, whether you realise it or not.
Alas, other browsers use it too without any warning, although you can turn it off it is not easily discoverable:
https://bugzilla.mozilla.org/show_bug.cgi?id=430741
As suggested, add sb.google.com or whatever endpoint is used to /etc/hosts or HOSTS file.